build: give the nightly a distinct icon and drop the longer label

The 17-character 'subtracks nightly' label just truncates in the launcher,
so revert the app_name override (debug and nightly show 'subtracks' like
the release) and distinguish the nightly with a recoloured launcher icon
(amber mark) instead. The debug and nightly variants share src/nightly/res,
so installDebug and installNightly look the same.

app/build.gradle.kts

@@ -30,7 +30,6 @@ android {
     buildFeatures {
         compose = true
         buildConfig = true
-        resValues = true
     }
 
     androidResources {
@@ -99,10 +98,13 @@ android {
         }
     }
 
+    sourceSets {
+        getByName("debug").res.srcDir("src/nightly/res")
+    }
+
     buildTypes {
         debug {
             applicationIdSuffix = ".nightly"
-            resValue("string", "app_name", "subtracks nightly")
         }
         release {
             isMinifyEnabled = true
@@ -115,7 +117,6 @@ android {
             initWith(getByName("release"))
             applicationIdSuffix = ".nightly"
             signingConfig = signingConfigs.getByName("debug")
-            resValue("string", "app_name", "subtracks nightly")
         }
     }
 }

app/src/nightly/res/drawable/ic_launcher_foreground.xml

@@ -0,0 +1,29 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="299.84"
+    android:viewportHeight="219.51">
+  <group android:scaleX="0.43"
+      android:scaleY="0.3147989"
+      android:translateX="85.4544"
+      android:translateY="75.20425">
+    <path
+        android:pathData="m23.84,-0c-12.76,0 -23.44,13 -23.65,25.12 -0.42,79.03 0,160.73 0,170.4 0,12.59 9.8,23.99 23.41,23.99l253.58,0c11.4,0 22.66,-12.38 22.66,-22.79L299.84,24.12c0,-10.8 -10.24,-23.81 -21.84,-23.81 -11.6,0 -254.16,-0.31 -254.16,-0.31zM39.05,25.28c0,0 217.71,0.71 223.67,0.71 6.07,0 12.17,6.83 12.17,12.06l0,142.25c0,8.97 -6.97,14.63 -12.48,14.64l-33.42,0.07c-5.32,0.01 -9.93,-7.19 -11.35,-10.61 -1.89,-4.55 -11.08,-25.75 -12.1,-28.1 -0.6,-1.38 -2.9,-2.83 -5.89,-2.83L98.33,153.45c-2.68,0 -4.89,2.87 -5.67,4.71 -1.12,2.66 -9.02,21.39 -11.63,27.57 -2.73,6.46 -4.37,9.06 -11.47,9.06l-30.97,0c-7.44,0 -13.69,-7.17 -13.67,-15.18l0.28,-139.51c0,-6.88 5.54,-14.83 13.85,-14.83z"
+        android:strokeWidth="0.9"
+        android:fillColor="#FFB300"
+        android:fillType="nonZero"
+        android:strokeColor="#00000000"/>
+    <path
+        android:pathData="M90.09,95.03m-32.1,0a32.42,32.1 90,1 1,64.21 0a32.42,32.1 90,1 1,-64.21 0"
+        android:strokeWidth="0.86"
+        android:fillColor="#FFB300"
+        android:fillType="nonZero"
+        android:strokeColor="#00000000"/>
+    <path
+        android:pathData="M209.94,95.03m-32.1,0a32.42,32.1 90,1 1,64.21 0a32.42,32.1 90,1 1,-64.21 0"
+        android:strokeWidth="0.86"
+        android:fillColor="#FFB300"
+        android:fillType="nonZero"
+        android:strokeColor="#00000000"/>
+  </group>
+</vector>